<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    #root{
      border:1px solid red;
      height:20px;
    }
  </style>
</head>
<body>
<div id="root"></div>
<script>
  var historyObj = window.history;
  //监听路径改变事件 表示将当前的状态变更了，弹出了
  window.onpushstate = (event) => {
    console.log(event.type,event.detail.state);
    root.innerHTML = window.location.pathname;
  }
  window.addEventListener('popstate', (event) => {
    console.log(event.type,event.state);
    root.innerHTML = window.location.pathname;
  });

  (function (historyObj) {
    let oldPushState = history.pushState;//缓存原生的pushState
    historyObj.pushState = function (state, title, pathname) {
      let result = oldPushState.apply(history, arguments);
      if (typeof window.onpushstate === 'function') {
        window.onpushstate(new CustomEvent('pushstate',{detail:{pathname,state}}));
      }
      return result;
    }
  })(historyObj);

  let oldHistoryLength = historyObj.length;
  setTimeout(() => {
    historyObj.pushState({ page: 1 }, { title: 'page1' }, '/page1');//page1
    console.log(historyObj.length-oldHistoryLength);
  }, 1000);
  setTimeout(() => {
    historyObj.pushState({ page: 2 }, { title: 'page2' }, '/page2');//page2
    console.log(historyObj.length-oldHistoryLength);
  }, 2000);
  setTimeout(() => {
    historyObj.pushState({ page: 3 }, { title: 'page3' }, '/page3');//page3
    console.log(historyObj.length-oldHistoryLength);
  }, 3000);
  setTimeout(() => {
    historyObj.back();//historyObj.go(-1);//page2
    setTimeout(()=>console.log(historyObj.length-oldHistoryLength),100);

  }, 4000);
  setTimeout(() => {
    historyObj.pushState({ page:4 }, { title: 'page4' }, '/page4');//page4
    console.log(historyObj.length-oldHistoryLength);
  }, 5000);
  setTimeout(() => {
    historyObj.go(1);
    console.log(historyObj.length-oldHistoryLength);//page4
  }, 6000);
</script>
</body>
</html>
